TERRAFORMING TERRA
We discuss and comment on the role agriculture will play in the containment of the CO2 problem and address protocols for terraforming the planet Earth.
A model farm template is imagined as the central methodology. A broad range of timely science news and other topics of interest are commented on.

Tuesday, August 23, 2011

Nanowire Contained Battery

As posted in the past, the drive
is to get all this chemistry working at nanoscale in order to vastly improve
energy density. We have come a long way.

I am not quite sure how this will
all come together, but it sounds like a great method of inserting energy
storage directly into the architecture of increasingly complex three
dimensional structures. Not having to
create a separate system to move energy in and out of a device must be useful.

Once the silicon chip was
mastered, it controlled design for decades.
Now we are mastering 3D architecture and it is as yet quite unclear what
the ultimate preferred mix will be.
These are all steps to that ultimate goal.

The world at large runs on lithium ion batteries.
New research at RiceUniversity shows that
tiny worlds may soon do the same.

The Rice lab of Professor Pulickel Ajayan has packed an entire lithium ion
energy storage device into a single nanowire, as reported this month in the
American Chemical Society journal Nano Letters. The researchers believe their
creation is as small as such devices can possibly get, and could be valuable as
a rechargeable power source for
new generations of nanoelectronics.

In their paper, researchers described testing two versions of their
battery/supercapacitor hybrid. The first is a sandwich with nickel/tin anode,
polyethylene oxide (PEO) electrolyte and polyaniline cathode layers; it was
built as proof that lithium ions would move efficiently through the anode to
the electrolyte and then to the supercapacitor-like cathode, which stores the
ions in bulk and gives the device the ability to charge and discharge quickly.

The second packs the same capabilities into a single nanowire. The
researchers built centimeter-scale arrays containing thousands of nanowire
devices, each about 150 nanometers wide. A nanometer is a billionth of a meter,
thousands of times smaller than a human hair.

Ajayan's team has been inching toward single-nanowire devices for
years. The researchers first reported the creation of three-dimensional
nanobatteries last December.

In that project, they encased vertical arrays of nickel-tin nanowires
in PMMA, a widely used polymer best known as Plexiglas, which served as an
electrolyte and insulator. They grew the nanowires via electrodeposition in an
anodized alumina template atop a copper substrate.

They widened the template's pores with a simple chemical etching
technique that created a gap between the wires and the alumina, and then
drop-coated PMMA to encase the wires in a smooth, consistent sheath. A chemical
wash removed the template and left a forest of electrolyte-encased nanowires.

In that battery, the encased nickel-tin was the anode, but the cathode
had to be attached on the outside.

The new process tucks the cathode inside the nanowires, said Ajayan, a
professor of mechanical engineering and materials science. In this feat of
nanoengineering, the researchers used PEO as the gel-like electrolyte that
stores lithium ions and also serves as an electrical insulator between
nanowires in an array.

After much trial and error, they settled on an easily synthesized
polymer known as polyaniline (PANI) as their cathode. Drop-coating the widened
alumina pores with PEO coats the insides, encases the anodes and leaves tubes
at the top into which PANI cathodes could also be drop-coated. An aluminum
current collector placed on top of the array completes the circuit.

"The idea here is to fabricate nanowire energy storage devices
with ultrathin separation between the electrodes," said Arava Leela Mohana
Reddy, a research scientist at Rice and co-author of the paper. "This
affects the electrochemical behavior of the device. Our devices could be a very
useful tool to probe nanoscale phenomenon."

The team's experimental batteries are about 50 microns tall - about the
diameter of a human hair and almost invisible when viewed edge-on, Reddy said.
Theoretically, the nanowire energy storage devices can be as long and wide as
the templates allow, which makes them scalable.

The nanowire devices show good capacity; the researchers are
fine-tuning the materials to increase their ability to repeatedly charge and
discharge, which now drops off after a about 20 cycles.

"There's a lot to be done to optimize the devices in terms of
performance," said the paper's lead author, Sanketh Gowda, a chemical
engineering graduate student at Rice. "Optimization of the polymer
separator and its thickness and an exploration of different electrode systems
could lead to improvements."

Rice graduate student Xiaobo Zhan is a co-author of the paper. The
Hartley Family Foundation, RiceUniversity, National Institutes of Health, Army
Research Office and MultidisciplinaryUniversity Research
Initiative supported the research. Read the abstracthere.

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About Me

Apr 2017 - 4.1 Mil Pg Views, March 2013 - Posted my paper introducing CLOUD COSMOLOGY & NEUTRAL NEUTRINO rigorously described as the SPACE TIME PENDULUM, September 2010 I am pleased to report that my essay titled A NEW METRIC WITH APPLICATIONS TO PHYSICS AND SOLVING CERTAIN HIGHER ORDERED DIFFERENTIAL EQUATIONS' has been published in Physics Essays(AIP) and appeared in their June 2010 quarterly. 40 years ago I took an honors degree in applied mathematics from the University of Waterloo. My interest was Relativity and my last year there saw me complete a 900 level course under Hanno Rund on his work in relativity,as well as differential geometry(pure math) and of course analysis. I continued researching new ideas and knowledge since that time and I have prepared a book for publication titled Paradigms Shift&. I maintain my blog as a day book and research tool to retain data and record impressions and interpretations on material read. Do join my blog and receive Four items of interest daily Monday through Saturday.